This invention relates generally to a direction control system for a boat. More specifically, the invention relates to an electronic direction control for trolling motors such as commonly associated with boats.
In the past, direction control systems for boats have suffered from a variety of defects which have resulted in an inability to quickly, accurately and precisely control the exact steering mechanism position desired. One recent electronic direction control system for boats generates a differential signal, the magnitude and polarity of which is dependent on the angular position of the steering wheel with respect to a vertical plane encompassing the longitudinal axis of the boat. According to its magnitude and polarity, this signal, which has a unique, maintained constant magnitude and polarity for each position of the steering wheel, biases one of two transistors in a switching circuit into such an operational state as to permit actuation of the appropriate one of two direction control motors.
Thus, regardless of the extent to which the desired and actual directions of the steering mechanism differ instantaneously, the angular velocity of the steering mechanism remains constant throughout all periods of direction correction which results in long transient response times. Also, since the angular velocity of the steering mechanism abruptly changes from a relatively large value to zero when the desired direction is reached, fractional direction changes become abrupt and difficult, if not impossible, to achieve and commonly occur with large mechanical overshoot in the position of trolling motor.
Furthermore, the trolling motor is limited to a relatively small range of directions thereby severely limiting maneuverability of the boat, since each direction control motor rotates the trolling motor propeller about a support shaft perpendicular to its drive shaft in opposite directions by forcing a piston into engagement with the trolling motor propeller gear assembly housing. Although other non-electronic direction control systems for boats have disclosed maneuverability ranges of up to .+-. 180.degree. relative to the instantaneous actual direction of travel, no known direction control systems have heretofore effectuated maneuverability ranges of greater than .+-. 180.degree.. Such a maneuverability range is highly desirous when navigating around obstacles in areas which highly restrict freedom of movement.